Radio-Heat Contrasts of UAVs and Their Weather Variability at 12 GHz, 20 GHz, 34 GHz, and 94 GHz Frequencies

Abstract

This work describes the procedure for determining the expected values of UAV radio-heat contrasts () and discusses its angular dependences, as well as the estimation of UAV detection distances at four points cm and mm ranges (12 GHz, 20 GHz, 34 GHz, and 94 GHz). This paper reveals the pronounced frequency dependence on brightness temperature () and of a fiberglass unmanned aerial vehicle (UAV) made from composite fiberglass materials. The quantified experiments are conducted against a sky background under various weather conditions and wave ranges. The qualitative physical interpretation of these properties and their frequency dependence is proposed, reflecting the coefficient values and radio brightness of the background. The weak influence of weather on the observed UAVs in the X and Ku bands are demonstrated along with the multiple decreasing detection characteristics and advantages of the W band under bad weather conditions (the appearance of rain or thick cloud). This work presents data on the values of UAV contrasts, observed against the background of the sky and the regularities noted could be useful for predicting the effectiveness of the proposed radiometric detection and tracking system.

The method for design of electromagnetic hybrid active-passive shielding by overhead power lines magnetic field

“…At the same time, naturally, it is necessary to take into account constraints [41] on the vector X desired parameters of a combined shield in the form of vector inequality and, possibly, vector equality…”

Method for design of two-level system of active shielding of power frequency magnetic field based on a quasi-static model

“…All fundamental results of the theory of automatic control systems are obtained on the basis of mathematical models of controlled processes in the form of systems of ordinary differential equations [29][30][31][32][33]. Analysis and synthesis of control systems for objects, given in the form of systems of differential equations, is a purely mathematical problem based on the structure of solving differential equations in an analytical form, or on numerical integration methods [34][35][36][37][38].…”

“…The task of synthesizing a magnetic field control system is usually complicated by significant uncertainties in the mathematical model of the control object [34][35][36][37]. Due to objective circumstances, such as the inaccuracy of the first level model, unmeasured external and internal disturbances, the actual values of the output coordinates will differ from the calculated ones [44][45][46][47].…”

“…To assess the impact of the magnetic field of power lines on the environment, most calculations were performed [33][34][35][36][37][38][39][40][41] based on the Biot-Savart-Laplace's law for elementary current…”

The method for design of combined electromagnetic shield for overhead power lines magnetic field

“…When solving this minimax problem numerically, in order to find the direction of movement, it is necessary to use the components of the gradient of the objective function for those variables over which the maximization is performed, and it is necessary to use the components of the antigradient (i.e., the gradient taken with the opposite sign) for those variables over which the minimization is performed [38][39][40][41][42][43].…”